PSI - Issue 79

Santi Marchetta et al. / Procedia Structural Integrity 79 (2026) 224–232

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Fig. 7. Hotspot approach validation: a) Steel welded T-joint; b) Ti6Al4V welded T-joint.

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Fig. 8. SED approach validation: a) steel t-joint; b) titanium t-joint.

5. Conclusions The objective of this study was to validate the hotspot and the SED approaches for fatigue design in steel and titanium welded joints. Data coming from literature was exploited to create a parametric finite element model which was used to apply both the methodologies in both joints. The results showed that for steel joints, the hotspot stress method proved to be consistent with the IIW recommendations, ensuring a conservative design when adopting the FAT 71 or FAT 80 curves. Similarly, the SED values fell within the scatter band proposed by Livieri and Lazzarin, confirming the reliability of this approach for fatigue design when the lower bound of the band is used as a reference, which corresponds to a survival probability of 97.7%.